Scientists settle the Cats vs Dog debate once and for all

It's an argument that's raged ever since humanity climbed out of its cave in search of a domesticated friend: which are better, cats or dogs?

Apparently tired of the endless back and forth, scientists have waded in to provide the 'conclusive' answer.

It's cats.

A study of 2,000 fossils by a team of international researchers has revealed that cats have not only been a hardier species than dogs, competition from felines has also contributed to the extinction of as many as 40 dog species.

Meow.

By examining the large fossil sample, the researchers were able to identify that the dog family originated North America roughly 40 million years ago (homo sapiens are thought to have been around for 200,000 years), and reached maximum diversity 22 million years ago.

Over 30 species of canine ancestors were making merry in the forests of North America when the cats arrived from the Asian continent - and changed everything.

"The arrival of cats to North America had a deadly impact on the diversity of the dog family," explains the report’s lead author Dr Daniele Silvestro of the University of Lausanne in Switzerland. "We usually expect changes in climate to play the overwhelming role in the evolution of species. Instead, competition among different carnivore species proved to be even more important for the dogs".

Competition from cats has seen the variation of dog species reduced to just nine in the North American continent (foxes, wolves and various other now-domestic dogs). The conclusion that cats are 'better' than dogs stems from the evidence that cat populations in other areas have never dwindled when competition was introduced by the arrival of dogs. However, the fossils can't explain exactly why cats are a superior survival force.

Dr Silvestro believes it might have something to do with the feline retractable claw: the dogs which thrived in North America were large creatures, adapted to hunting their prey in packs that were skilled in running. Some dogs were adapted for ambushing their prey, much like cats - but a lack of retractable claws saw this group die out.

"The cats have retractable claws which they only pull out when they catch their prey," said Dr Silvestro. "This means they don’t wear them out and they can keep them sharp. But the dogs can’t do this, so they are at a disadvantage to the cats in an ambush situation."

Significantly, the study revealed that competition from similar species of animals might have a greater influence on evolution than previously thought, with the report concluding that cats "must have been more efficient predators than most of the extinct species in the dog family".